The present invention concerns centrifugal processing apparatus and, more particularly, apparatus employing unbilical tubing which is rotated with respect to a stationary base.
Centrifugal processing systems are used in many fields. In one important field of use, a liquid having a suspended mass therein is subjected to centrifugal forces to obtain separation of the suspended mass.
As a more specific example, although no limitation is intended herein, in recent years the long term storage of human blood has been accomplished by separating out the plasma component of the blood and freezing the remaining red blood cell component in a liquid medium, such as glycerol. Prior to use, the glycerolized red blood cells are thawed and pumped into the centrifugating wash chamber of a centrifugal liquid processing apparatus. While the red blood cells are being held in place by centrifugation, they are washed with a saline solution which displaces the glycerol preservative. The resulting reconstituted blood is then removed from the wash chamber and packaged for use.
The aforementioned blood conditioning process, like other processes wherein a liquid is caused to flow through a suspended mass under centrifugation, necessitates the transfer of solution into and out of the rotating wash chamber while the chamber is in motion. Thus while glycerolized red blood cell and saline solution are passed into the wash chamber, waste and reconstituted blood solutions are passed from the chamber. To avoid contamination of these solutions, or exposure of persons involved in the processing operation to the solutions, the transfer operations are preferably carried out within a sealed flow system.
One type of centrifugal processing system which is well adapted for the aforementioned blood conditioning process uses the principles of operation described in Dale A. Adams U.S. Pat. No. 3,586,413. The apparatus of the Adams patent establishes fluid communication between a rotating chamber and stationary reservoirs through a flexible interconnecting umbilical cord without the use of rotating seals, which are expensive to manufacture and which add the possibility of contamination of the fluid being processed.
The primary embodiment of the Adams patent comprises a rotating platform which is supported above a stationary surface by means of a rotating support. A tube is connected to the stationary support along the axis of the rotating platform and the rotating support, with the tube extending through the rotating support and having one end fastened to the axis of the rotating platform. A motor drive is provided to drive both the rotating platform and the rotating support in the same relative direction at speeds in the ratio of 2:1, respectively. It has been found that by maintaining this speed ratio, the tube will be prevented from becoming twisted. An improvement with respect to this principle of operation, comprising a novel drive system for a centrifugal liquid processing system, is disclosed in Khoja, et al. U.S. Pat. No. 3,986,442. In the Khoja, et al. patent, a novel drive system is provided for driving a rotor assembly at a first speed and a rotor drive assembly at one-half the first speed, in order to prevent an umbilical tube from becoming twisted.
A centrifugal processing system has been discovered in which the umbilical cord is connected at its ends to the main axis of the system, but extends freely without being supported or guided by a tube or other guide means. It has been found that there is significant strain at the umbilical tube connection points and for that reason lateral support at the connection points has generally been provided by fairleads or other suitable supporting means. Some lateral supporting means have required lubrication, or bearings or the anchoring system has been found to be relatively expensive. The utilization of a tubular guide arm or the like for the umbilical cord has reduced strain in certain instances, but such guide arm requires additional structural elements which add cost to the system and present a greater possibility of malfunction.
Thus it is desirable to have the ability to use an umbilical cord segment which is connected at its ends to the main axis of the system, but which swings freely during the centrifugal processing operation. It is an object of the present invention to provide means which allow the umbilical cord to withstand high centrifugal forces without fracturing.
Another object of the present invention is to provide the umbilical cord with a localized stiffness at its anchor points.
A still further object of the present invention is to provide centrifugal processing apparatus in which a free-flight type of umbilical cord carries strain relief means which allow the umbilical cord to withstand high centrifugal forces without expensive means of lateral support.
Another object of the invention is to provide strength to the umbilical cord at its anchor points without requiring bearings and/or lubrication systems.
Another object of the present invention is to provide a centrifugal processing apparatus using a free-flight type of umbilical cord segment which is simple in construction and efficient to manufacture.
A further object of the present invention is to provide means to anchor umbilical tubing to the torque arm of centrifugal processing apparatus and also to the processing chamber portion.
Other objects and advantages of the present invention will become apparent as the description proceeds.